You can also NOT see the health drop down, if your weapon is very ineffective against the enemy's shielding. This is where you need to switch to a different type of weapon real quick.
When you stop shooting the enemy, the health bar will stay visible for a few seconds, then fade out. It also fades out when you kill the enemy.
This is the first step toward giving the player feedback in Conquest on how well he's doing against his enemy. Earlier a few people expressed frustration at how hard it was to know whether or not their weapon was actually damaging the enemy -- now they can watch it happen. I want to thank you guys for bringing this up so I'd do something about it.

There's one more really cool side-effect to this new health bar - poison weapons have become really awesome. Now that the player can actually watch the poison take effect and see how strong it is, he can realize just how worth-while the weapon can be. Poison arrows ROCK now.

EEEEWWWWWWW!!! My screenshots got milk all over them!
The next step will be to make numbers hover in mid-air in front of the monster as you shoot it. The health bar uses only one entity per monster, but this could use up to 4 per monster (assuming you actually do 4 digits of damage). I already know how to make this work, I just have to do it.
A long time ago somebody made a mod that did this. In their mod, if you kept shooting the enemy, the numbers displaying damage would continue to count up the total (instead of spawning new numbers). After you stopped doing damage, the numbers would begin to float up and would eventually disappear, unless you started doing damage again.
This is what I want to do. The code should be simple (I was surprised at how easy the HP bar was), and the effect for the player will be awesome. It'll be cool watching the damage count up as he blasts the enemy with an effective weapon.
It should also provide more hints to the player on the inner workings of the shield system.
Cheers for now. I'll keep you updated.